Human Capital Explained: Definition, Examples, Wages and Growth

Human capital is the stock of skills, knowledge, experience and health that workers carry with them and that makes each hour of their work more productive. Schooling, job training, practice on the job and good health all add to it. Economists call it capital because building it costs time and money today and pays off as higher output and higher wages in later years, just as a machine does.

The idea is closely associated with the economists Theodore Schultz and Gary Becker, who treated spending on education as an investment rather than ordinary consumption. In AP Macroeconomics, human capital is a source of growth in Topic 5.6, Economic Growth, and a policy lever in Topic 5.7, Public Policy and Economic Growth. In AP Microeconomics it appears in Topic 5.2, Changes in Factor Demand and Factor Supply.

What counts as human capital

Human capital is anything inside a person that raises what that person can produce. It is measured per worker, not by headcount, so hiring ten more people with no new skills adds labor but leaves human capital per worker unchanged.

• Knowledge: math, reading, and the facts of a trade, such as electrical codes.
• Skills: welding a clean joint, writing code that runs, diagnosing an engine fault.
• Experience: speed and judgment from doing a job many times.
• Health: a healthy worker misses fewer days and works better while present.

The capital is the set of skills a diploma stands for. Some economists argue that part of the pay gain from schooling comes from the diploma revealing ability the worker already had, which is the signaling theory of education.

How human capital is built

1. Formal education: high school, college, trade school. The cost is tuition plus the wages a student gives up.

2. Job training: courses, certifications and apprenticeships.

3. Experience: on-the-job training happens while a person works, with no extra classroom time.

4. Health care and nutrition: these raise the number of productive hours a worker can supply over a career.

Each route gives something up now for more output later. That trade-off is what makes education an investment, and it is why the opportunity cost of time can be the largest cost of schooling, as the worked example below shows.

Human capital vs physical capital

Both kinds of capital raise output per worker, and both shift long-run aggregate supply to the right. They differ in where they live and who owns them. The human capital vs physical capital comparison gives a short version.

Physical capital means tools and machines, never money; the factors of production guide explains why. The two kinds work together: a diagnostic computer is worth little to a mechanic who cannot read it, and a trained mechanic is held back by worn-out tools.

Human capital and productivity

Productivity is output per worker or per hour worked. Human capital raises it directly.

Hypothetical example. A bike repair shop has 5 mechanics who together finish 40 repairs a day.

1. Output per mechanic before training = 40 / 5 = 8 repairs a day.

2. All 5 complete a certification course. The shop now finishes 50 repairs a day with the same tools.

3. Output per mechanic after training = 50 / 5 = 10 repairs a day.

4. Productivity growth = (10 - 8) / 8 x 100 = 25 percent.

No one was hired and no equipment was bought, so the whole gain came from human capital. The labor productivity calculator runs the same steps.

Human capital and wages

A firm hires workers up to the point where the marginal revenue product of the last worker equals the wage. For a firm selling in a competitive market, MRP = marginal product x output price. Training raises marginal product, so it raises MRP, and labor demand shifts right. The factor markets and marginal revenue product guide covers the full hiring rule.

Hypothetical example. The bike shop sells each repair for $30, and the market wage is $150 a day.

• Before training: MRP equals the $150 wage at the 5th mechanic, so the shop hires 5.
• After training: MRP equals $150 at the 6th mechanic, so the shop hires 6.

The MRP column is the shop's labor demand curve, and training moved every value up. On a market graph with the wage on the vertical axis and quantity of labor on the horizontal axis, demand for skilled mechanics shifts right, raising both the equilibrium wage and employment. Try it in the factor markets sandbox or check a row with the MRP calculator. Labor demand is a derived demand, so skills pay only when they produce something buyers want.

See it move

Make it move

A competitive labor market, where labor demand (MRP) and labor supply set the wage. Tap it to drag the curves, open the full version, or put it on your own site free, or turn it into a five-minute class activity.

Human capital and long-run economic growth

On the production possibilities curve. Put capital goods on one axis and consumer goods on the other. More human capital lets the economy produce more of both, so the whole curve shifts outward. Schools also use resources that could have made consumer goods, so a society that invests more in education gives up some consumption now for a curve that sits further out later. The PPC guide shows both moves, and the PPC sandbox lets you shift the curve.

In the AD-AS model. Put the price level on the vertical axis and real GDP on the horizontal axis. Long-run aggregate supply is vertical at potential output. A more skilled workforce raises potential output, so LRAS shifts right. If aggregate demand stays put, the new long-run equilibrium has higher real GDP and a lower price level. See SRAS vs LRAS for the difference between the two supply curves.

Human capital also helps growth last. Like machines, extra schooling per worker eventually runs into diminishing returns, but skilled workers are also the ones who invent, adopt and improve new technology, which is what keeps output per worker rising in the long run. The full set of growth sources is in economic growth explained, and the Solow growth model guide shows how capital per worker reaches a steady state.

Education can also create a positive externality, with benefits that spill over to people beyond the student. A free market then tends to produce less education than is best for society, which is one argument for public schooling and student aid.

Worked example: an education decision as an investment

All numbers are hypothetical. Jordan has just finished high school.

• Option A: work now at $30,000 a year.
• Option B: a two-year technician program at $8,000 a year in tuition, with no wage while enrolled, then work at $42,000 a year.

Step 1: tuition. 2 x $8,000 = $16,000.

Step 2: forgone wages. 2 x $30,000 = $60,000 of pay given up.

Step 3: full opportunity cost. $16,000 + $60,000 = $76,000. Rent and food are left out, because Jordan pays them under either option.

Step 4: yearly gain. $42,000 - $30,000 = $12,000 more each year after the program.

Step 5: payback period. $76,000 / $12,000 = about 6.33 years of work after the program, or about 8.33 years counting the two in school.

Step 6: simple return. $12,000 / $76,000 x 100 = about 15.8 percent of the cost recovered each year.

Forgone wages are nearly four times the tuition, which is why the opportunity cost guide stresses the value of time. Check Step 3 with the opportunity cost calculator.

Timing matters too. A dollar earned later is worth less than a dollar today. At a hypothetical 5 percent interest rate, the $12,000 gain in year 10 is worth 12,000 / 1.05^10 = 12,000 / 1.6289 = about $7,367 today, which the present value calculator confirms. Present value goes beyond the AP course; the opportunity cost logic in Steps 1 to 3 is standard AP material.

Human capital on the AP exam

Expect to identify education, training or health as human capital, show it as an outward PPC shift or rightward LRAS shift, and explain how training raises MRP and shifts labor demand right.

Common mistakes:

• Counting more workers as more human capital. Population growth adds labor, not skill per worker.
• Shifting only AD for a growth question. Government spending on education raises AD in the short run, but the human capital it builds raises capacity, so the long-run growth effect is a rightward LRAS shift.
• Leaving out forgone wages when asked for the cost of school.

Practice both sides in the economic growth module and the factor markets module.